In some situations a remote ESD station is required. These are to be installed nearby logical locations (next to escape routes, at the gate or in nearby equipment.
The ESD station is always used in combination with a control system e.g. an HPU or WHCP.
It is usually a low pressure valve (push/pull or selector) that blocks a pneumatic or hydraulic supply line from the control panel, which will be pressurized during normal conditions.
In the control panel will be a pressure transmitter, pressure switch or control circuit that will respond on changes in output pressure.
In event of an emergency the ESD station can be manually activated. Pressure will then be released (vented) and detected in the control system.